1. Field of the Invention
This invention relates to wireless telecommunication systems. More particularly, the invention concerns the provision of service features for wireless calls in a wireless telecommunication system.
2. Description of the Prior Art
In existing wireless telecommunication systems, service features for wireless calls (e.g., call forwarding, call waiting) are implemented in an MSC (Mobile Switching Center). When a wireless subscriber roams beyond the jurisdiction of the subscriber's home MSC, a temporary subscriber database is created during the mobile registration process by the visited MSC. This database is part of a storage resource called the VLR (Visitors Location Register). The visited MSC creates the VLR database by querying an HLR (Home Location Register) associated with the subscriber's home network MSC, which reports the subscriber's service feature information back to the visited MSC. This service feature query interchange is supported by existing resources of the PSTN (Public Switched Telephone Network). Once a call is originated or terminated on behalf of the visiting wireless subscriber, call control logic in the VLR can be executed locally. However, frequent resynchronization between the VLR and the HLR may be required.
It is submitted that the administration of service features for wireless calls could be improved if the visited MSC did not have to re-create database information that already exists in the wireless subscriber's HLR. Among other things, eliminating this information re-creation step would tend to reduce registration-related delays. It is also noted that no basic or supplementary service features are typically available for wireless data calls in prior art systems. The above-described wireless service feature support is only provided in the voice domain, where separate bearer and signaling channels are used. A further deficiency of the prior art is that subscriber information stored in PSTN resources such as an HLR are generally available to the public. Service providers who wish to keep their subscriber information confidential thus cannot do so.